1 files changed, 18 insertions, 25 deletions

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index db15f9ba7c0b..bc84e125c6bc 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1111,9 +1111,7 @@ void tty_write_message(struct tty_struct *tty, char *msg)
  *              Locks the line discipline as required
  *              Writes to the tty driver are serialized by the atomic_write_lock
  *      and are then processed in chunks to the device. The line discipline
- *      write method will not be involked in parallel for each device
- *              The line discipline write method is called under the big
- *      kernel lock for historical reasons. New code should not rely on this.
+ *      write method will not be invoked in parallel for each device.
  */
 
 static ssize_t tty_write(struct file *file, const char __user *buf,
@@ -1213,7 +1211,7 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p)
  *      be held until the 'fast-open' is also done. Will change once we
  *      have refcounting in the driver and per driver locking
  */
-struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
+static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
                 struct inode *inode, int idx)
 {
         struct tty_struct *tty;
@@ -1819,8 +1817,10 @@ got_driver:
                 /* check whether we're reopening an existing tty */
                 tty = tty_driver_lookup_tty(driver, inode, index);
 
-                if (IS_ERR(tty))
+                if (IS_ERR(tty)) {
+                        mutex_unlock(&tty_mutex);
                         return PTR_ERR(tty);
+                }
         }
 
         if (tty) {
@@ -2050,7 +2050,6 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
 /**
  *      tty_do_resize           -       resize event
  *      @tty: tty being resized
- *      @real_tty: real tty (not the same as tty if using a pty/tty pair)
  *      @rows: rows (character)
  *      @cols: cols (character)
  *
@@ -2058,41 +2057,34 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
  *      peform a terminal resize correctly
  */
 
-int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
-                                        struct winsize *ws)
+int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
 {
-        struct pid *pgrp, *rpgrp;
+        struct pid *pgrp;
         unsigned long flags;
 
-        /* For a PTY we need to lock the tty side */
-        mutex_lock(&real_tty->termios_mutex);
-        if (!memcmp(ws, &real_tty->winsize, sizeof(*ws)))
+        /* Lock the tty */
+        mutex_lock(&tty->termios_mutex);
+        if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
                 goto done;
         /* Get the PID values and reference them so we can
            avoid holding the tty ctrl lock while sending signals */
         spin_lock_irqsave(&tty->ctrl_lock, flags);
         pgrp = get_pid(tty->pgrp);
-        rpgrp = get_pid(real_tty->pgrp);
         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 
         if (pgrp)
                 kill_pgrp(pgrp, SIGWINCH, 1);
-        if (rpgrp != pgrp && rpgrp)
-                kill_pgrp(rpgrp, SIGWINCH, 1);
-
         put_pid(pgrp);
-        put_pid(rpgrp);
 
         tty->winsize = *ws;
-        real_tty->winsize = *ws;
 done:
-        mutex_unlock(&real_tty->termios_mutex);
+        mutex_unlock(&tty->termios_mutex);
         return 0;
 }
 
 /**
  *      tiocswinsz              -       implement window size set ioctl
- *      @tty; tty
+ *      @tty; tty side of tty
  *      @arg: user buffer for result
  *
  *      Copies the user idea of the window size to the kernel. Traditionally
@@ -2105,17 +2097,16 @@ done:
  *      then calls into the default method.
  */
 
-static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
-        struct winsize __user *arg)
+static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
 {
         struct winsize tmp_ws;
         if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
                 return -EFAULT;
 
         if (tty->ops->resize)
-                return tty->ops->resize(tty, real_tty, &tmp_ws);
+                return tty->ops->resize(tty, &tmp_ws);
         else
-                return tty_do_resize(tty, real_tty, &tmp_ws);
+                return tty_do_resize(tty, &tmp_ws);
 }
 
 /**
@@ -2540,7 +2531,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         case TIOCGWINSZ:
                 return tiocgwinsz(real_tty, p);
         case TIOCSWINSZ:
-                return tiocswinsz(tty, real_tty, p);
+                return tiocswinsz(real_tty, p);
         case TIOCCONS:
                 return real_tty != tty ? -EINVAL : tioccons(file);
         case FIONBIO:
@@ -2785,6 +2776,8 @@ void initialize_tty_struct(struct tty_struct *tty,
         INIT_WORK(&tty->hangup_work, do_tty_hangup);
         mutex_init(&tty->atomic_read_lock);
         mutex_init(&tty->atomic_write_lock);
+        mutex_init(&tty->output_lock);
+        mutex_init(&tty->echo_lock);
         spin_lock_init(&tty->read_lock);
         spin_lock_init(&tty->ctrl_lock);
         INIT_LIST_HEAD(&tty->tty_files);